Abrasive-disk wheel



S. M. BULLOCK AND H. S. LLOYD.

ABRASLVE DISK WHEEL.

APPLICATION men JULY 15, 1919.

1 35 1 ,Gffl 1 Patented Aug. 31, 1920.

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I ence marked thereon,

UNITED STATES PATENT OFFICE.

SAMUEL M. BULLOCK, OF CHICAGO, AND HARRY S. LLOYD, 01? OAK PARK,

ILLINOIS.

ABRASIVE-DISK WHEEL.

Patented Aug. 31, 1920.

Application filed July 15, 1919. Serial No. 310,968.

To all whom it may concern:

Be it known that we, SAMUEL M. BULLOCK and HARRY S. LLOYD, citizens ofthe United States, and residents of the city of Chicago and village ofOak Park,

have invented certain new and'useful Improvements in Abrasive-DiskWheels; and we do hereby declare that the following is a full, clear,and exact description of the same, reference being had to theaccompanying drawings, and to the numerals of refer- Which form a partof this specification.

This invention relates to abrasive disks, more particularly those usedin disk grinders in which the face of the wheel is employed for grindingpurposes of our Patent No. 1,311,550, issued July 29th, 1919.

The problem of constructing satisfactory abrasive disks is a diflicultone and various attempts have been made to solve it with only partialsuccess.

Abrasive disks must be made relatively very thin to avoidthe diskbreaking under the action of centrifugal force and also to avoid thenecessity of supporting the axle which carries the disk on each side ofthe grinding surface.

en glue is employed as a binder the practical limit of thickness isabout but disks ma e by our improved method may be considerably thicker.Thus an 18 disk made by our process may be thick and a 53" disk *3"thick. ,Usually the thickness of the disks is less than 1-}% and morerarely be tween 11],; and 5% of their diameter.

It is impractical to make such disks by baking owing to the shrinkageand distortion produced by the heat. especially in a disk as thin asabove specified.

Tf. glue is employed as the binder the disks must be madeexcessivelythin since as soon asthe surface layer of adhesive has wornofl and the glue binder is exppsed the heat .produced by the friction ofthe disk against the surface beingground causes the glue to melt and Howover the surfaces of the abrasive'particles and thereby inhibits theircutting action.

y using a binder composed of magnesium chlorid and magnesium oxid agrinding disk can be made which will retain its respectively, in. thecounty of Cook and State of Illinois,

. pletely away.

' Difficulty has, however, been experienced in mounting disks of thischaracter owing to the trouble involved in cementing the disk to itssupport. We have found that this difficulty may be overcome by using afabric base for the disk. The fibrous nature of the fabric provides anexcellent bonding medium between the abrasive and magnesium mixture onthe one hand and also provides a satisfactory support for the glue bywhich the disk so formed may be secured to the metallic surface of adriving wheel.

It has further been found that if the Wet mixture of abrasive, magnesiumchlorid and magnesite is applied to a dry fabric disk the latter absorbsthe magnesium chlorid solution from the mixture and seriously interfereswith the setting so that instead of a rock-like surface a soft friablesurface is obtained.

This difficulty may be overcome by wetting the fabric before applyingthe abrasive mixture thereto either with plain water or preferably witha strong-solution of magnesium chlorid.

It is an object, therefore, of this invention to provide an improvedgrinding disk which will retain its cutting qualities to the last andwhich may be readily and securely attached to a driving wheel.

Other and further important objects of this invention will be apparentfrom the disclosures in the specification and drawings.

The invention (i118. preferred form) is illustrated in the drawings andhereinafter more fully described.

On the drawings:

Figure 1 is a front elevation of a disk and driving wheel embodying thefeatures of the present invention.

Fig. 2 is a section on the line 2-2 of Fig. 1.

As shown on the drawings:

The fabric disk 2 is first wetted, preferably with a strong solution ofmagnesium chlorid. Then a mixture of abrasive particles, magnesite andmagnesium chlorid is applied to the disk to form a layer 1 of thedesired thickness. The whole then sets in the course of a few hours to ahard rock like disk by reason of the peculiar proper- Ice ties ofmagnesium chlorid and its power to combine with magnesite to form a hardsubstantially insoluble oxy'chlorid.

The abrasive mixture may conveniently be'made in the followingproportions:

75% of a suitable abrasive such as carborundum,

12 of magnesium chlorid,

12%% of calcined magnesite.

Suflicient water is employed to bring the magnesium chlorid intosolution.

For wetting the fabric disk a solution of magnesium chlorid containingabout 85% by weight of the salt may be used;

In applying the abrasive mixture to the fabric disk any convenientmethod may be employed such as pressing, tamping, poundor rolling eitherby hand or machine.

After the disk has set it may be secured to a driving wheel 3 byapplying any suitable adhesive such as sodium silicate or water glass tothesurface of the fabric 2 and, after clamping the disk against thewheel, allowing the same to dry. This will serve to hold the diskrigidly associated with the driving wheel until the disk has become wornnecessitating removal thereof. The

earner fabric and remaining portion of abrasive may be torn from thewheel or the glue or cement may be dissolved by any suitable solvent topermit easy removal of the fabric 1 and the remainder of the abrasivethereon.

We are aware that numerous details of construction may be varied througha wide range without departing from the principles of this invention,and we therefore do not purpose limiting the patent granted otherwisethan necessitated by the prior art.

We claim as our invention:

An abrasive disk for disk grinders comprising a fabric disk and a layerof abrasive particles bound together and to the fabric bymagnesiumchlorid and magnesite, the ratio of magnesium chlorid to magnesite beinghigher in the fabric than in the layer of abrasive material.

In testimony whereof we have hereunto subscribed our names in thepresence of two subscribing witnesses.

i L M. BULLOCK. REY S. LLOYD.

Witnesses:

EARL ll/f. HARDINE, Grams W. HILLS, Jr.

